Liquid crystal display device with prevention of defective disconnection of drain/pixel electrodes by forming two conductive layers on top of entire pixel electrode and then removing a portion of both therefrom

Abstract

A method for fabricating an LCD device includes providing first and second substrates and has a contact hole exposing a portion of the source and drain regions formed by removing a portion of the first and second insulation layers and removing the second insulation layer of the upper portion of the pixel electrode. The method also includes forming a third conductive layer on the first substrate; forming source and drain electrodes electrically connected to the source and drain regions through the contact hole by patterning the third conductive layer and exposing the second conductive layer of the upper portion of the pixel electrode; and forming a liquid crystal layer between the first and second substrates.

1. A method for fabricating a liquid crystal display device, comprising:
 providing first and second substrates; 
 forming an active layer having a source region, a drain region and a channel region on the first substrate; 
 forming a first insulation layer on the first substrate; 
 forming first and second conductive layers on the first substrate; 
 forming a gate electrode, a gate line and a pixel electrode on the first substrate by patterning the first and second conductive layers; 
 forming a second insulation layer on the first substrate; 
 forming a contact hole exposing a portion of the source and drain regions by removing a portion of the first and second insulation layers and removing the second insulation layer of the upper portion of the pixel electrode except for a portion in a periphery of the pixel electrode; 
 forming a third conductive layer on the first substrate, wherein the third conductive layer directly contacts with the second conductive layer in which both cover the entire upper portion of the pixel electrode; 
 forming source and drain electrodes electrically connected to the source and drain regions through the contact hole by patterning the third conductive layer; 
 opening the pixel electrode by removing the second and third conductive layers of the upper portion of the pixel electrode except for a portion in the periphery of the pixel electrode, wherein the drain electrode directly connected to the pixel electrode without any other contact hole; and 
 forming a liquid crystal layer between the first and second substrates. 
 
     
     
       2. The method of  claim 1 , wherein the active layer is formed as a silicon layer. 
     
     
       3. The method of  claim 2 , wherein the silicon layer is formed as a crystallized silicon film. 
     
     
       4. The method of  claim 1 , wherein the gate electrode and the gate line is formed of a dual layer of the first and second conductive layers by patterning the first and second conductive layers. 
     
     
       5. The method of  claim 1 , wherein the pixel electrode is formed of the first conductive layer by patterning the first and second conductive layers. 
     
     
       6. The method of  claim 5 , wherein the upper portion of the pixel electrode remains a pixel electrode pattern of the second conductive layer. 
     
     
       7. The method of  claim 6 , wherein removing the second insulation layer on the pixel electrode exposes the pixel electrode pattern. 
     
     
       8. The method of  claim 1 , wherein the first or the second conductive layer is formed of one of indium tin oxide (ITO) and indium zinc oxide (IZO). 
     
     
       9. The method of  claim 1 , wherein the second conductive layer is formed of one of aluminum, an aluminum alloy, tungsten, copper, chromium and molybdenum. 
     
     
       10. The method of  claim 1 , further comprising:
 patterning the second conductive layer on the pixel electrode to remain a second conductive layer pattern electrically connected to the drain electrode in a periphery of the upper portion of the pixel electrode. 
 
     
     
       11. The method of  claim 10 , wherein the third and the second conductive layers on the pixel electrode are patterned when a portion of the drain electrode and the second conductive layer pattern on the pixel electrode are electrically connected. 
     
     
       12. The method of  claim 1 , wherein a mask for forming the contact hole includes a pixel electrode pattern for opening the pixel electrode region. 
     
     
       13. The method of  claim 12 , wherein removing the second insulation layer on the pixel electrode using the mask exposes the second conductive layer on the pixel electrode. 
     
     
       14. The method of  claim 1 , further comprising forming source and drain regions by injecting an impurity ion to a region of the active layer using the gate electrode as a mask after forming the gate electrode. 
     
     
       15. The method of  claim 1 , wherein forming the contact hole and removing the second insulation layer on the pixel electrode are substantially simultaneously preceded. 
     
     
       16. The method of  claim 1 , wherein forming the source and drain electrodes opening the pixel electrode are substantially simultaneously preceded. 
     
     
       17. A method for fabricating a liquid crystal display device, comprising:
 providing first and second substrates; 
 forming an active layer on the first substrate; 
 forming a first insulation layer on the first substrate; 
 forming a gate electrode, a gate line and a pixel electrode formed of a dual layer having first and second conductive layers on the first substrate; 
 forming a second insulation layer exposing a portion of the active layer and the pixel electrode; 
 forming source and drain electrodes electrically connected to the portion of the active layer through a contact hole by patterning a third conductive layer over the entire pixel electrode and opening the pixel electrode by removing the second and third conductive layers of an upper portion of the pixel electrode except for a portion in a periphery of the pixel electrode, wherein the drain electrode directly connected to the pixel electrode without any other contact hole of the first conductive layer; and 
 forming a liquid crystal layer between the first and second substrates. 
 
     
     
       18. The method of  claim 17 , wherein the pixel electrode is formed of the first conductive layer by patterning the first and second conductive layers. 
     
     
       19. The method of  claim 18 , wherein an upper portion of the pixel electrode remains a pixel electrode pattern of the second conductive layer. 
     
     
       20. The method of  claim 17 , wherein forming the second insulation layer includes:
 forming the second insulation layer on the first substrate; and 
 forming the contact hole exposing a portion of the source and drain regions of the active layer by removing a portion of the first and second insulation layers and exposing the pixel electrode by removing the second insulation layer on the pixel electrode except for the portion of the periphery of the pixel electrode. 
 
     
     
       21. The method of  claim 20 , wherein forming the contact hole and removing the second insulation layer on the pixel electrode are substantially simultaneously preceded. 
     
     
       22. The method of  claim 17 , wherein the first conductive layer of the pixel electrode is exposed by patterning the second conductive layer on the pixel electrode so as to remain the second conductive layer pattern electrically connected to the drain electrode at an edge of the upper portion of the pixel electrode.